Multipole circuit breaker



J. G. JACKSON MULTIPOLE CIRCUIT BREAKER May 12, 1953 Filed Feb. 28, 1951 2 Sheets-Sheet l mum.

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J. G; JACKSON MULTIPOLE CIRCUIT BREAKER y May 12, 1953 Filed Feb. 28, 1951 2 Sheets-Sheet 2 RM. ,n SM m n mja T T F n Patented May 12, 1953 MU LTIPOLE CIRCUIT BREAKER John G. Jackson, Detroit, Mich., assigner to Square D Company, Detroit, Mich., a corporationof Michigan Application'February'ZS, 1951, SerialNo. 213,166

(-Cl. 20G- 88) 10 Claims.

This invention relates to electric circuit breakers automatically operable in response to current overload and more particularly to automatic electric circuit breakers of the multipole type.

The object of this invention is to provide an improved multipole circuit breaker mechanism in which all poles will be released in response to an overload in any one pole in the circuit breaker.

Another object of the invention is to provide a multipole circuit breaker mechanism in which the switching means for individual poles are independently latched and in which current responsive release of one switching means will cause release of the other switching means in response to movement of the one switching means.

Another object or" the invention is to provide a multipole circuit breaker mechanism in which the switching means for individual poles are independently latched and in which there is a common means for engaging and releasing said latching means and interengaging means on each .of said switching means and common means so that upon current responsive release of one of .said switching means it willinove to engage said common means and effect movement thereof to unlatch all of said switching means.

Another object of the invention is `to provide a multipole circuitbreaker mechanism `in accordance with the preceding object in which the common means .is magnetically attracted upon heavy overload to effect substantially simultaneous release of all the switching means.

Other objects and features rof the invention will be readily apparent to those skilled in the art from the specication and appended drawings illustrating certain preferred embodiments in which:

Figure 1 is a vertical sectional View of the .circuit breaker according to the present invention.

Figure 2 is a transverse sectional View alongY line `lI--II of Figure 1.

Figure 3 is an exploded perspective View of the common trip mechanism.

The circuit breaker illustrated in the drawings as one form ofthe present invention includes a generally cup-shaped insulating base I having a generally centrally disposed dividing wall 2 serving to insulate the breaker poles from each other. Within each .of the compartments formed by the central wall `2 and the sidewalls of the base I is mounted a circuit breaker pole mechanism, the separate poles having fcertain duplicate parts which will now be described.

Each of the-.poles includes a stationary contact 3 mounted on aconnector 4 which is supported on an end ledge of vthecircuit breaker' exterior by a spun-over portion ci a threaded metallic insert E which receives a terminal screw 'I. The chamber about the stationary Contact 3 is lined with insulating sheets 9 of ber or other material and within this chamber is a movable contact .Il carried upon the end of a rigid switching contact bar I2. The top edge ci the Contact bar I2 is provided with a slot at I3 which receives the inner end oi aslot within the longer leg of a U-shaped member I4 to form a pivotal `mounting for the Contact bar I2. The member I4 is guided for rectilinear movement at right angles to the back of the base by means of formations within the base.

A connector I5 is mounted upon an end ledge I6 atthe opposite end of the breaker by a spunover portion of a metallic insert I'I. The interior endof the connector I5 has a central pressed in arm lil upon which is rigidly secured `a bimetallic member I9. Adjustable means indicated generallyat 2l is provided for adjusting the calibration oi the breaker by moving the arm I8.

Fixed to the bimetallicrnember I9 by means of a rivet I0 near its midpoint is a resilient spring strip 22 formed to provide a latching tip at 23 ona lower leg 2.5 which is biased by its resiliency awayirom the plane of the bimetallic member I9, but whose position is limited by the engagement with the back of the bimetalof the flange 24 formed at the end 0f the leg 25. Theother leg 26 of the spring strip 22 is formed as shown to extend toward the front oi' the breaker to bias a rotatable insulating supporting shaft 21 in a counter-clockwise direction, as viewed in Figure 1. On the side of thebimetallic member I9 opposite the resilient strip 22 is a magnetic yoke 28 of generally U-shape with its legs on opposite sides of the bimetallic member. The yoke 28 is also mounted by the rivet IB.

A flexible lead 3| interconnects the free end of the bimetallic member I9 and the contact bar I2, and the end of the contact bar I2 remote from the contact I I is latched in operating position by means of .the latching tip 23 on vthe leg 25 of the resilient spring member 22. A compression spring 32 provides a bias for holding the contact I I against the stationary contact 3 when the breaker is closed and biases the Contact I2 for rotation about the pivotal engagement of the notch I3 with the member M when the breaker is tripped, such rotation being prevented by enggementof latching tip 23 with the end of bar Upona shaft 34 is pivotally mounted an operating handle 35 having an interior cam surface which includes a nat stable manual Off portion 36 and a resetting tip 3l. To close off the top of the circuit breaker, there are provided common cover yplates 38 and 39 sealably attached to .the base as by spun-over portions 3 of metallic rivets (not shown). A light spring 4I is provided to operate on the handle 35 to provide a denite position On therefor.

The single pole mechanism heretofore described is duplicated for each pole desired in the breaker which are here illustrated as two. To form these single poles into a multipole circuit breaker, there is provided a common trip mechanism which is illustrated in vperspective in Figure 3 and Which comprises a pair of magynetizable armature members 42 and 43 slotted lat 44 and 45 as shown in Figures 2 and 3 to permit movement of the ends of contact bars I2 therethrough, The armature members 42 and 43 are rigidly mounted within the insulating shaft 2l so that the armature members and shaft `rotate as a unit. Upon the armature members 42 and 43, adjacent slots 44 :and 45, are mounted cams 46 engageable by pins 4l mounted one each ladjacent the latching ends of the contact bars lI2. The armature members 42 and'43 are positioned opposite the legs of Ithe yoke 28 so as to be attracted thereto upon energization of the `yoke in response to the passage of heavy overload `currents through the .bimetallic member I9 which in effect forms a single turn about the magnetic circuit. The armature members 42 and 43 are also positioned so that as they rotate in a clockwise direction, :as viewed in Figure 1, they will engage their respective latching tips 23 to move them into unlatching position. It is apparent Ithat the width of latching tips 23 is greater than Ithe width of the adjacent portions of slots 44 and 45, as shown in Figure 3, so that yarmatures y42 and 43 may engage their respective latching tips. The exterior portions of the operating handle 35 are rigidly connected together by means of a U-sha-ped metallic member 48 which joins .the handles together for common movement as a unit.

The operation of the circuit breaker will now be described. The parts are shown in Figure 1 Iwith the breaker in the open position. Rotation of the handle 35 in a counterclockwise direction as viewed in Figure 1 will allow the U-shaped member I4 to move forwardly under the bias of spring 32 to rotate contact bar l2 about its pivotal engagement with the latching tip 23 of the resilient spring strip 22 to move the movable contact II into engaged position with the stationary contact. 3, placing Ithe breaker in the On position. 'I'o again place the parts in` manual open circuit position, the handle is rotated in a clockwise direction `from its On position to the Ofi position of Figure 1.

Upon an occurrence of a sustained moderate overload through any one of the circuit breaker poles, the bimetallic member I9 for that pole :will become heated and will flex to move in a clockwise direction to move the spring 22 mounted thereon Ibodily toward the left as viewed yin Figure 1, thus moving its latching tip 23 to a position to release the end of the cooperatingcontact bar I2 which then rotates in a clockywise direction under the bias of compression spring 32 about its pivotal engagement with the longer leg of the U-shaped member I4. This movement of the contact bar I2 forces its pin 4'I against its associated cam 4S and thereby rotates the armature members 42 and 43 and shaft 21 about their pivotal mounting in a clock- Wise direction as Viewed in Figure 1. As the armatures 42 and 43 are moved toward their respective yoke members 28, the one associated with the unreleased pole will engage the latching tip 23 for that pole and will move it toward its supporting bimetal member against the bias of strip 22 into unlatching position to thus release all contact bars I2 upon thermal current responsive release of any one of them.

A further .feature of this invention is apparent upon the occurrence of a heavy overload and short circuit currents through one or more of the breaker poles. Upon such an occurrence, the magnetic attraction between the yoke 28 and the armatures becomes sufficient to rotate the armatures bodily in a clockwise direction until they engage the latching tips 23 and move them toward their supporting bimetallic members and into unlatching position. As the armatures are rigidly connected together, they will effect substantially simultaneous release of all of the contact bars upon the attraction of any of the armatures caused by heavy overload or short circuit currents in the pole with which it is associated.

After an automatic opening of the circuit breaker, it may be reset by rotating handle 35 into its extreme clock-wise position in which the reset tip 3l forces the U-shaped member to its rearward position in which the contact carrying end of the contact bar I2 engages the base and causes the contact bar to rotate in a counterclockwise direction as the member I4 is forced rearwardly until the latching end of the contact bar passes below the latching tip 23. Release of the handle 35 will vpermit the parts to return to the position of Figure 1 under the bias of spring 32 with the end of the contact bar engaging the latching tip 23 and with the movable contact II in the Off position.

While this invention has been described inv y interpretation within the terms of the following claims.

What is claimed is:

1. In a multipole automatic electric circuit breaker, a plurality of pairs of separable contacts and elements individual to each pair releasable to effect separation of the corresponding pair of contacts, means mounting one of each pair of contacts upon the element associated with that pa1r of contacts, independently operable latching means for each of said plurality of elements, currentresponsive tripping means for effecting unlatching of the latching means including both thermal and magnetic tripping means individual to each element of said breaker and energized in response to current flow through the pair of contacts controlled by their associated element,

means mounting said individual magnetic trip- Iping means for common movement as a unit to cause unlatching of the latching means for all elements due to a current overload through any pair of contacts, said individual thermal tripping means efiecting unlatching of the latching means I of the1r associated individual element due to a current overload through the associated pair of contacts, and means on each of said elements lengageable with said magnetic means to eiect unlatchng movement of all said latching means in response to release of any element.

2. In a multipole automatic electric circuit breaker, a plurality of pairs of separable co-ntacts and elements individual to each pair releasable to effect separation of the corresponding pair of contacts, means mounting one of each lpair of contacts upon the element associated with that pair of contacts, independently operable latching means for each of said plurality of elements, a bimetallic member in series circuit with. each pair of contacts, each latching means being movable by its associated bimetallic member in response to overload current therethrough to release its associated element, magnetic means common to all pairs oi contacts and energized in response to overload current through any pair to move all of said latching means to unlatching position, and means on each element engageable With said lmagnetic means when an element is released by movement of a bimetallic member to effect unlatching movement of all the latching means.

3. In a multipole automatic electric circuit breaker, a plurality of pairs of separable contacts and elements individual .to each pair releasable to effect separation of the corresponding pair of contacts, independently operable latching means for each of said plurality of elements, a bimetallic member in series circuit with each pair of contacts, said latching means including resilient strips mounted on said bimetallic members and movable therewith and relative thereto, a magnetic circuit for each pair of contacts energized by current flow therethrough and each including an armature attracted on overload through its associated pair of contacts to move the associated latching means into unlaltching position, said armatures being rigidly connected for common movement as a unit, a pin mounted on each of said elements and adjacent to the latched end of each of said elements, a cam surface on each of said armatures, said pins engaging said cam surfaces after bimetal release of said elements to move said armatures and latching means and release -all the elements in response to overload current through any pair of contacts.

4. In a multipole automatic electric circuit breaker, a plurality of pairs of separable contacts and elements individual to each pair releasable to effect separation of the corresponding pair of contacts, means mounting one of each pairof contacts upon the element associated with that Ipair of contacts, independently operable latching means for each of said plurality of elements, current responsive tripping means for eiecting unlatching of the latching means, means common -to all elements of said circuit breaker operable to move said latching means to unlatched -position, and surfaces on said elements engageable with said common means to effect unlatching movement of all the latching means in response to an overload in any one or more pairs of contacts.

5. In -a multipole automatic electric circuit breaker, a plurality of pairs of separable contacts and elements individual to each pair releasable to eect separation of the corresponding pair of contacts, means mounting one of each pair of contacts upon the element associated with that pair of contacts, independently operable latching means for each of said plurality of elements. current responsive tripping means for eiecting unlatching of the latching means, means common to all elements of said circuit breaker and -operable to move said latching means to unlatched position, abutments on each yof said elements adjacent the latched ends of said elements, cam surfaces on said common means, said abutment engaging said cam surface after release by said current responsive tripping means to move said common means and the latcliing means to release all the elements in response to overload current through any pair of contacts.

6. In a multipole automatic electric circuit breaker, a plurality of pairs of separable contacts and elements individual to each pair releasable `to eiiect separation of the corresponding pair of contacts, means mounting one of each pair of contacts upon the element associ-ated with that pair of contacts, independently operable latching means for each of said plurality of elements, a bimetallic member in series circuit with each pair of contacts, said latching means including resilient strips mounted on said bimet-allic members and movable therewith and relative thereto, means common to all elements of said circuit breaker and operable to move said latching means relative to said bimetallic members to unlatched position, and abutments on said elements engageable with said common means to effect unla-tehing movement of all latching means in response to an overload in any one or more pairs of contacts.

7. In a multipole automatic circuit breaker, a plurality of pairs of separable contacts, an element individual to each of said pairs for carry- .ing one of the associated pair of contacts, means biasing said elements for movement, independently operable latching means for each of said elements, said elements being releasable to eiect separation of the corresponding pair of contacts, current responsive tripping means for eiecting unlatching of each of said latching means in- -cluding thermal and magnetic means, each of lsaid last mentioned means being energized in response to current flow through the element with which it is associated, said magnetic tripping means being operatively common to all poles of the breaker and causing unlatching of the latching means for all other poles in response to operation of the latching means in one pole by said thermal means.

8. The device as deined in claim 7 in which said elements carry abutments for operating the magnetic means upon release of the elements by said thermal means.

9. The device as dened claim 7 so vconstructed and arranged that all magnetic means are simultaneously operated to eect release of all latching means upon the occurrence of high current overloads in one or all poles.

10. The device as defined in claim 8 in which said magnetic means carry cam surfaces engageable by said abutments upon release of said elements by said thermal means.

JOI-IN G. JACKSON.

References Cited in the ile of this patent UNITED STATES PATENTS Number Name Date 970,600 Atwood Sept. 20, 1910 973,889 Stuart Oct. 25, 1910 2,140,360 Jennings Dec. 13, 1938 2,184,372 Von Hoorn Dec. 26, 1939 2,419,125 Dorfman et al. Apr. 15, 1947 FOREIGN PATENTS Number Country Date 638,997 Germany Nov. 26, 1936 

